The present invention relates to an electrochemical storage device having a metallic, gas-tight storage device housing in which an electrode stack formed from a plurality of electrode plates stacked on one another is accommodated, having a box-like stack insulation which is arranged between the storage device housing and the electrode stack, is made from an electrically insulating material which surrounds the electrode stack, including those sides of are adjacent electrode stack which are adjacent narrow sides of the electrode plates.
The fundamental electrochemical storage device of the generic type has a metallic, gas-tight storage device housing in which an electrode stack formed from a plurality of electrode plates stacked on one another is accommodated, with recombiners being arranged between individual electrode plates of the same polarity, for example between the negative electrode plates, and separators being arranged between the electrode plates of different polarity. The electrode plates are connected via their respective current-collecting lug to a terminal yoke which, for its part, is connected in an electrically conductive fashion to the terminal pillar, which leads outwards. Arranged between the storage device housing and the electrode stack is a stack insulation which is made from an electrically insulating material and which surrounds the electrode stack completely at the sides and at the bottom in order to avoid short circuiting of electrode plates of different polarity via the metallic storage device housing. A gas-conducting network is arranged between the stack insulation and the electrode stack so that in the event of a high incidence of gas these gases can flow virtually unimpeded inside the electrochemical storage device. The gas conducting network is a strip of a plastic network which is guided from a side wall of the electrode stack arranged transverse to the flat sides of the electrode plates via the bottom of the electrode stack to the opposite side wall of the electrode stack, so that the gas-conducting network is arranged on the lateral rims of the electrode plates at which the gas emerges. In the region of the bottom of the electrode stack, the gas conducting network is followed in the direction of the housing bottom by a separator, then by a catalyst member arranged in a frame and subsequently by the bottom of the stack insulation.
The gas-conducting network is attached during the manufacture of the electrochemical storage device to the relevant sides of the stack insulation, for example by means of spot welding. The bottom of the stack insulation is fitted in advance with the catalyst frame, the catalyst plate and the separator. Subsequently, the fitted stack insulation is arranged around the electrode stack provided with the cover and the terminal pillars and inserted jointly into the storage device housing, which is open on the cover side, and the housing is sealed in a gas-tight fashion.
This type of production requires many individual parts and in terms of the production cycle is bound up with many steps, as a result of which, inter alia, the costs for the production of an electrochemical storage device are high. In order for only a slight play to occur between the individual components of the electrochemical storage device, and in order for the electrode stack to have effective thermal contact with the storage device housing, the individual components of the insulation must further be produced with very narrow tolerances, so that the production costs for the electrochemical storage device are increased once more.
Such electrochemical storage devices are generally operated with a partial vacuum, so that the sides of the storage device housing which are assigned to the gas conducting networks press the gas-conducting network against the lateral rims of the electrode plates. As a result, for example, individual gas-conducting conduits can be squeezed off or sealed by a displacement of the gas-conducting network, and/or the gas-conducting network can be pressed into the rims of the electrode plates and/or of the separators, as a result of which electrode plates of different polarity can be short circuited. In both cases, the quality of the electrochemical storage device is lowered.
An object of the present invention is to improve the fundamental storage device of the above-described generic type so that it can be produced more cost effectively in conjunction with high quality and a lower expenditure.
This and other objects are achieved by the present invention which provides an electrochemical storage device comprising a metallic, gas-tight storage device housing, an electrode stack formed from a plurality of electrode plates stacked on one another accommodated in the storage device housing, a box-like stack insulation between the storage device housing and the electrode stack, made from an electrically insulating material and surrounding the electrode stack at the sides of the electrode stack which would bear directly against the housing interior, and gas conduits arranged between the stack insulation and the electrode stack on peripheral sides of the electrode stack formed by the peripheral edges of the electrode plates, to form gas outlet sides, wherein the gas conduits are material protuberances in the stack insulation, are spaced apart from one another and cross over the narrow sides of the electrode plates.
Due to the material protuberances which are impressed into the stack insulation and project towards the electrode stack and are spaced apart from one another, a separate gas-conducting network becomes dispensable, and this is bound up with a saving in costs and a higher production accuracy. In addition, the working steps relating to the gas conducting network are dispensed with, making the production process more simple and less expensive. Moreover, the gas conduits extending between the material protuberances, as previously happened with the lines of the gas-conducting network, can no longer be displaced and thereby sealed. The advantage of the invention comes to light particularly clearly when looking at the cost advantage, which amounts here to more than one to ten by comparison with the old design.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.